TECHNICAL AND ECONOMICAL STUDY OF AN ORC DEDICATED TO THE PRODUCTION OF ELECTRICITY FROM A GEOTHERMAL SOURCE

asme-orc2015 Tracking Number 91

If the ORC are proving to be an effective solution to produce mechanical or electrical power from low temperature heat source, this also makes them more sensitive to the sizing of their equipment. In fact, due to the Carnot cycle between a source and a heat sink close in temperature, the pinch involved in the evaporators or condensers have new consequences on the surfaces of exchanges. In these specific conditions, technical and economical compromises must be determined in order to make ORC competitive. This paper focuses on the technical-economic study of an ORC supercritical with propane, without regenerator dedicated to the production of electricity from a geothermal source. A program is written in Matlab environment. It describes how in a first time, the four main equipment (pump, geothermal exchangers, turbine and condenser) are dimensioned by applying the theorem of equipartition of entropy production in the heat exchanger geothermal. Their costs are estimated in relation to their sizing parameters for an arbitrary chosen design ambient temperature. In a second time, it describes how their behaviour change according the weather along the year. A typical ambient temperature distribution along the year is estimated with Meteonorm and used to calculate the yearly production. In a third time the same geothermal source is virtually placed in four places in the world with different weathers. By the previous described methods four different ORC plants are designed and the comparison between each is presented. A discussion is open about the consequence of heat sink temperature variations on the characteristics of equipment, designed at a fixed ambient temperature but used at a variable ambient temperature.